1. Field of Invention
The current invention relates to methods and systems for assembling multi-component nano-structures and novel multi-component nano-structures.
2. Discussion of Related Art
The study of nano-materials often includes fabrication, characterization, and applications of the nano-structures. A vast variety of nano-structures made of metallic, semiconductive, magnetic, and polymer materials have been fabricated into 0D dots (S. Link and M. A. El-Sayed, J. Phys. Chem. B, 103, 8410 (1999)), rings, 1D wires/tubes (F. Q. Zhu, G. W. Chern, O. Tchernyshyov, X. C. Zhu, J. G. Zhu and C. L. Chien, Phys. Rev. Lett. 96, 27205 (2006)), 2D films (K. Robbie and M. J. Brett, J. Vac. Sci. Tech. A. 15, 1460 (1997)), and 3D architectures (J. E. G. J. Wijnhoven and W. L. Vos, Science, 281, 802, (1998)).
Among them, 1D nano-structured wires/tubes have become the focus of recent research. Extensive work reveals that nano-wires and nano-tubes have unique electronic (Z. Zhang, X. Sun, M. S. Dresselhaus and J. Y. Ying, Phys. Rev. B. 61, 4850 (2000)), optical (X. Lu, T. Hanrath, K. P. Johnston and B. A. Korgel, Nano Lett. 3, 93 (2003). T. T. Hanrath and B. A. Korgel, J. Am. Chem. Soc. 124, 1424 (2001). J. D. Holme, K. P. Johnston, R. C. Doty and B. A. Korgel, Science, 287, 1471 (2000)), magnetic (T. M. Whitney, J. S. Jiang, P. C. Searson, and C. L. Chien, Science 261, 1316 (1993)), and mechanical properties (E. W. Wong, P. E. Sheehan and C. M. Lieber, Science, 277, 1971 (1997)), owing to the quantum confinement effect and large surface area.
Even though device prototypes made of nano-wires and nano-tubes have been demonstrated, such as logic units (Y. Huang, X. Duan, Y. Cui, L. J. Lauhon, K.-H. Kim and C. M. Lieber, Science, 294, 1313 (2001)) in microchips, nano-lasers (M. Huang, S. Mao, H. Feick,d H. Yan, Y. Wu, H. Kind, E. Weber, R. Russo and P. Yang, Science, 292, 1897, (2001)), optical switches (H. Kind and H. Yan and M. Law and B. Messer and P. Yang, Adv. Mater. 14, 158 (2002)), and sensors for cellular and molecular diagnosis (S. R. Nicewarner-Pena, R. G. Freema, B. D. Reiss, L. He, D. J. Pena, D. Walton, R. Cromer, C. D. Keating and M. J. Natan, Science, 294, 137, (2001). Y. Cui and Q. Wei and H. Park and C. M. Lieber, Science, 293, 1289, (2001)), the application of nano-wires as technologically useful materials has been greatly hindered by the difficulties in precision handling of nano-wires.
To date, nano-wires containing magnetic segments have been aligned by applying external magnetic fields using electromagnets or permanent magnets over centimeter lengths (M. Chen, L. Sun, J. E. Bonevich, D. H. Reich, C. L. Chien, and P. C. Searson, Appl. Phys. Lett., 82, 3310 (2003). M. Tanase, L. A. Bauer, A. Hultgren, D. M. Silevitch, L. Sun, D. H. Reich, P. C. Searson, and G. J. Meyer, Nano Lett., 1, 155 (2001)). A magnetic segment is incorporated into the nano-wires to achieve the alignment. Because the magnetic force is a weak force, it is difficult to induce any motion on nano-wires. More recently, holographic optical traps have been used to manipulate semiconductive nano-wires (R. Agarwal, K. Ladavac, Y. Roichman, G. Yu, C. M. Lieber, D. Grier, Optical express, 13, 8906 (2005)). The efficiency, however, is quite low because only several nano-wires can be manipulated at a time. Elaborate instrumentations are also required. Dielectrophoretic force induced by AC electric fields has been used to transport nano-wires and nano-tubes (D. L. Fan, F. Q. Zhu, R. C. Cammarata and C. L. Chien, Appl. Phys. Lett. 85, 4175 (2004); B. Edwardsa, N. Engheta, S. Evoy, J. Appl. Phy. 102, 024913 (2007)). However, the direction, velocity, or trajectory cannot be controlled without extremely complicated electronic design and computer programming. Thus, there is a need in the art for improved methods and systems for precision manipulation of nano-structures.